I am a fat non-lazy overachiever!! I believe that personality and maturity play the biggest role in intelligence and drive. I doubt that being fat determined it but maybe some lazier people aren't as smart because they not only put less effort into studying but into everyday life. The cause of being overweight varies from person to person as well. No scientific conclusion can be based on 2 subjects because you don't have a baseline for average to rule out the fact that they may be on the far ends of the spectrum.